The present invention relates to loading assemblies used for testing vehicles. More particularly, the present invention relates to a loading assembly for applying at least one of a longitudinal force, a lateral force, a vertical force, a braking moment, a steer moment and a camber moment to a vehicle spindle.
Many test fixtures have been advanced to apply forces and moments to a vehicle spindle in order to simulate driving or road conditions. These test fixtures often include separate actuators to apply vertical, longitudinal and lateral forces as well as braking moments to the vehicle spindle. U.S. Pat. Nos. 4,733,558; 5,083,453 and 5,465,615 disclose three such test fixtures.
Commonly, the test fixtures include a wheel adapter housing that is mounted to the vehicle spindle. Two vertical struts are joined to the perimeter of the wheel adapter housing and are used to, transfer the longitudinal forces, the vertical forces and the braking moments to the vehicle spindle. A center downwardly projecting tang located between the vertical struts and also joined to the perimeter of the wheel adapter housing is joined to a lateral strut, which is used to transmit lateral force developed from an actuator. Otherwise, a plurality of struts can be used to induce a lateral force or steer and camber moments.
Although the above-identified test fixtures are often quite capable of applying longitudinal forces, vertical forces, lateral forces, braking moments, steer moments and/or camber moments to the vehicle spindle, vehicle fender well sheet metal can create clearance problems that make application of the fixtures to some vehicles difficult.
There is also an on-going need to reduce or minimize xe2x80x9ccrosstalkxe2x80x9d. Crosstalk exists when unwanted or undesired loads are induced in the vehicle spindle due to the displacement of the vehicle spindle or application of selected forces or moments to the vehicle spindle. For example, in some prior art designs, a longitudinal force can be induced in the vehicle spindle due to steer displacement of the vehicle spindle. Crosstalk commonly is associated with the design of the loading assembly, and in particular, the arrangement and coupling the loading-assembly components.
An improved loading assembly that addresses one, some or all of these concerns is therefore desired.
A loading assembly used in a vehicle spindle test fixture includes a wheel adapter housing that is mountable to a vehicle spindle. A pair of vertical struts are provided. Each vertical strut is joined to the wheel adapter housing at spaced-apart first pivot connections. A bell crank is coupled to each end of the vertical struts at spaced-apart second pivot connections. An actuator is pivotally coupled to the bell crank at a third pivot connection. The location of the second pivot connections relative to the third pivot connection approximates the location of the first pivot connections relative to the spindle axis.
A second broad aspect of the present invention is a loading assembly having a wheel adapter housing that is mountable to the vehicle spindle, a first bell crank, and a connecting strut pivotally connected to the wheel adapter housing and the first bell crank. A first actuator is operably connected to the first bell crank to displace the wheel adapter housing substantially along the spindle axis. A pair of second bell cranks are pivotally connected to the first bell crank. A pair of second connecting struts are provided. Each second connecting strut is pivotally connected to one of the second bell cranks and operably connected to the wheel adapter housing to selectively displace the wheel adapter housing. At least one second actuator is operably connected to the second bell cranks.